The command sencha app build --locale en production does not work. Here is the error text:

C:\@repositories\element2\client\ews-office-app>sencha app build --locale en production
SenchaCmd v6.2.2.36
[INF]Using GPL version of Ext JS version 6.2.0.981from C:\@repositories\element2\client\ext.
[INF]The implications of using GPL version can be found here (http://www.sencha.com/products/extjs/licensing).
[ERR]No build descriptors selected